The present invention relates to an orthopedic support device, and particularly pertains to a polycentric knee stabilizer capable of rendering full support and stability to the knee joint at rest and in motion.
The human knee is the largest joint of the body, but due to its natural structure is the most vulnerable. The leg consists principally of a lower bone called the tibia and an upper bone known as the femur. The femur and the tibia are hinged together at the knee joint which consists of the femural condyles supported in engagement with bearing like pads positioned on the upper end of the tibia called the medial and lateral menisci. The joint is held together by numerous ligaments, muscles and tendons, including the lateral ligaments and internal ligaments. The patella is a similarly supported bone positioned in front knee joint primarily acting as a shield for it. During flexion, the axes above which the natural movement between the tibia and femur takes place shifts backward. During extension of the knee, the axes shifts forwardly. The knee joint has a locking feature when the joint is in full extension. This latter feature permits the knee joint to be capable of supporting great weight vertically. The joint is susceptible to damage if over extended or subjected to lateral or rotational trauma. If one or more of the ligaments or other elements of the knee structure are damaged, the joint may become unstable, allowing the knee joint to wobble laterally, move forward or backward, or rotate about its generally vertical axis. Corrective surgery may also result in knee joint instability particularly during the healing process. The components of the knee joint are capable of self-healing if the joint is maintained in a suitable stable position for a proper period of time. It is also important for recovery to have the support for the healing joint elements equipped with means for permitting controlled movement when exercising the joint elements to restore their strength and natural range. It is often necessary for particular individuals, such as athletes, to continue their activity and strenuous occupations despite inherent weakness in a knee joint due to prior trauma or during recuperation. It is desirable therefore to provide support and protection to the knee joint for such persons during periods when it is subject to further injury.
Various methods and devices are available which attempt to provide such additional support and stability to the knee. Adhesive taping, resilient knee supports, or elastic bandages are used, but they provide insufficient protection. For more critical conditions, and potentially hazardous exposures, it is necessary to have stronger knee stabilizers. Available stabilizers for such purposes do not provide the requisite strength, natural motion, range, precise smooth control, and ease of adjustment needed. It is desirable that such a stabilizer cause minimal restriction to movement and be comfortable to wear. The stabilizer must be securely attached to the leg, and provide great longitudinal and lateral support in all planes, yet be capable of permitting full range of natural joint flexion and extension. For recuperative use, it is further desirable that the same device be effective in controlling the range of knee movement in flexion, extension and rotation, and be readily adjustable during use to establish and maintain the desired movement of the joint within the natural range of rotation in a manner that simulates the shifting rotational axes of a normal knee. Applicant's invention meets these and other requirements and overcomes the deficiencies of available knee stabilizers.